1. Field of Invention
This patent application relates to termite control, specifically to a method and system for termite interception and baiting designed to suppress or eradicate colonies of termites, thereby protecting objects such as structures, agricultural crops and trees against termite attack.
2. The Prior Art
For many years, the indiscriminate application of environmentally persistent pesticides at ground level in and around the foundation of structures at points of possible termite entry and attack, in order to form a barrier to termite entry, has been the only viable method for effective, long term protection of structures and other items against termite attack. However, concerns over the effect of such tactics on the short and long-term health of persons occupying treated structures and on the general environment surrounding the structures has forced a reassessment of termite control tactics by the termite control industry. This reassessment has included efforts to develop viable, low impact alternatives to indiscriminate "wholesale" applications of pesticides currently used to prevent or control termite attack.
One potential replacement method for barrier treatments for termite control is termite baiting. Termite baiting is the aggregation of termites at a fixed point and their elimination due to their consumption of a toxicant-containing bait placed at the point of aggregation. This method of protection has several advantages over current methods. It involves the use of only a fraction of the amount of pesticide active ingredient that would have been expended to accomplish protection of an object, such as a structure, using barrier methods. The pesticide bait can optionally be placed in a secured, tamperproof station that prevents movement of bait out of the station into the general environment, yet permits termite entry into the station. Placement of bait in a station also minimizes the potential for exposure of humans, especially children, and large animals to the bait. Perhaps most importantly, termite baiting results in the elimination or suppression of the termite colony, not just the exclusion of members of the colony from the point of attack or object being protected. Because a termite bait must be consumed by termites in order to be effective, a technique must be developed to consistently and repeatedly make the bait available for consumption by members of a termite colony at a fixed point over a long enough period of time for the bait to have the intended toxic effect on the colony. However, to accomplish this, a baiting system must deal with several issues that left unresolved, make a baiting method and/or system unlikely to succeed.
Because termites consume cellulose for nutrition, termites are a serious threat throughout much of the world to structures or other objects containing wood or other cellulose containing components. Termites can be divided into two basic classifications, subterranean and non-subterranean. Subterranean termite colonies live primarily in the ground and forage for cellulose containing food items in the earth or above ground by building a system of closed mud tunnels to traverse from the ground to the above ground food source. Non-subterranean termite colonies live above ground near or within the food source they are consuming.
For several reasons, it is desirable that termite bait be applied only after contact has been established with a termite colony and termites are aggregated for the purpose of feeding on the bait at a fixed, arbitrary baiting point. These reasons include minimization of the amount of bait manufactured, potential deterioration of bait if it is left in place for long periods of time in anticipation of prospective termite attack, minimization of the potential for unintended exposure of children and pets to the bait, etc. Therefore, any responsible baiting method and/or system must anticipate the need to first aggregate termites at a point with a nontoxic aggregating medium and only then apply toxic bait at that point.
As currently developed, bait stations are devised to achieve detection and suppression of termites by utilizing a system comprised of a housing with openings and a set of interchangeable bait cartridges. In the device described in U.S. Pat. No. 5,329,726, granted Jul. 19, 1994, the architecture of the cartridges is such that they have a plurality of openings that correspond to the openings in the housing when placed within the housing.
The problem of termite disturbance is addressed in U.S. Pat. No. 5,329,726 by providing that the cartridges used for identification and suppression of termites each have openings that align with the housing openings when the cartridges are inserted within the housing. After detection of termites in nontoxic bait cartridge used during the detection stage, that cartridge is removed and replaced with a toxic bait cartridge of corresponding architecture. In accordance with the teaching of patentee in U.S. Pat. No. 5,329,726, the substitution of the pesticide containing cartridge for the nontoxic cartridge will not disturb pre-existing galleries or passageways established by termites to provide access between the termite colony and the openings in the outer housing of the control station because the outer housing remains fixed relative to the terrain and the openings in the pesticide cartridge remain in alignment with the openings in the housing. Accordingly, termites are provided with continued access to the pesticide-containing bait cartridge within the housing, thus permitting continuous feeding and the transport of pesticide-containing food to the termite colony through the pre-established connections between the colony and the bait stations.